A non-volatile memory system may be implemented as a plurality of dies. At least one of the dies may be configured as a memory die, which includes memory cells that store data in the memory system. Another of the dies may be configured to function as a controller that controls or otherwise manages the storage of the data in the memory system. Other types of dies may be possible, such as those that deliver power, perform routing or switching operations to communicate signals between the controller die and the memory dies, or those that include volatile memory for temporary storage of data or other information. The dies in the memory system other than the memory dies may be collectively referred to as accessory or auxiliary dies.
Design specifications for next-generation memory systems continually require an increase in storage capacity, and more memory dies may be needed in order to meet these requirements. As more memory dies are needed, more accessory dies may also be needed.
One way a plurality of memory dies can be integrated together is by orienting them in a planar fashion, such as by mounting each of them on a respective portion of a surface of a substrate. Integrating memory dies in this manner continually increases the surface area as more and more dies are added to the memory system. Another way a plurality of memory dies can be integrated together is by stacking the memory dies on top of one another. Stacking the memory dies instead of mounting them adjacent to each other on a substrate surface may reduce or minimize the increase in surface area as more memory dies are added to the memory system.
In addition, one way memory dies may be electrically connected to accessory dies is through wire bonding. A signal path formed via wire bonding may couple die capacitance of a plurality of memory dies in parallel. As a result, increasing the number of memory dies may increase an overall capacitance of the signal path, which in turn may limit the number of memory dies that can be included in the system.
Also, the memory dies and the accessory dies may be packaged together in various ways. In some example configurations, a memory die stack may be mounted on one portion of a surface of a substrate, one or more accessory dies may be mounted on another portion of the substrate surface and wire bonded to the memory die stack, and the memory die stack and the accessory dies may be encapsulated together. The substrate carrying the memory die stack and the accessory dies may, in turn, be mounted on a second or main substrate, which may also have mounted to it other substrates carrying other memory die stacks and/or additional accessory dies, such as a controller die and a volatile memory die. The components mounted on the second substrate may be encapsulated together via a second encapsulation process. Although such a configuration is able to contain all of the components of a non-volatile memory system, it may have undesirably large dimensions (length, height, and width) due to having multiple components separately mounted to different portions of a surface of a main substrate. Also, since wire bonding may be used, the number of memory dies that may be included in a single stack may be limited. If such a number is less than the total number of memory dies needed to meet the storage capacity requirements, multiple separately-encapsulated memory die stacks may be included, which is another factor that contributes to the relatively large dimensions of the memory system.
To reduce the overall size of the memory system while increasing its storage capacity, a design or configuration that increases the number of memory dies within a single encapsulated stack, decreases the number of substrates needed to carry the memory dies, and minimizes the number of components mounted on the main substrate may be desirable.